Study on Traffic Flow Control Based on Matlab Data Analysis

With urbanization and increased vehicle usage, understanding the exposure to air pollutants inside the vehicles is vital for developing strategies to mitigate associated health risks. In-vehicle air quality influences the comfort of the driver during long commutes and has gained significant interest. This study focuses on studying in-vehicle air quality in the San Francisco Bay Area in California, an urban setting with significant traffic congestion and varied emission sources and road conditions. Each trip is about 80.5 km (50 miles) in length, with commute times of approximately one hour. Two low-cost portable sensors were employed to simultaneously measure in-vehicle pollutants (PM2.5, PM10, and CO2) during morning and evening rush hours from May 2023 to December 2023. Seasonally averaged PM2.5 varied from 5.07 µg/m3 to 6.55 µg/m3 during morning rush hours and from 4.38 µg/m3 to 4.47 µg/m3 during evening rush hours. In addition, the impacts of local PM2.5, vehicle ventilation settings, and speed of the vehicle on in-vehicle PM concentrations were also analyzed. CO2 buildup in vehicles was studied for two scenarios: one with inside recirculation enabled (RC on) and the other with circulation from outside (RC off). With RC off, CO2 concentrations are largely within the 1100 ppm range recommended by many organizations, while the average CO2 concentrations can be three times high under recirculation mode. This research suggests that low-cost sensors can provide valuable insights into the dynamics of air pollution in the in-vehicle microenvironment, which can better help commuters reduce health risks.

Gain scheduling based ventilation control with varying periodic indoor air quality (IAQ) dynamics for healthy IAQ and energy savings

Jalan Martapura Lama is an alternative road connecting Banjarmasin, Martapura and Banjarbaru city and it is under the administration of Banjar Regency. The existence of Sungai Lulut Market in Kilometer 05 consistently causing congestion to the area, especially during peak hours. The purpose of this study is to determine the impact of market activities on the performance of Jalan Martapura Lama KM 05 indicated by the degree of saturation (DS) and the value of the level of road service.
 The method of primary data collection was by conducting traffic surveys and measuring geometric conditions in the site manually on Tuesday to Thursday, 06-08 February 2018 during the morning rush hour (07.00-08.00 a.m), the noon hour (12.00-14.00 p.m) and afternoon rush hour (16.00 to 18.00 p.m) while the secondary data was obtained from the internet. The calculation refers to Indonesian Highway Capacity Manual (MKJI) 1997.
 From the calculation results it can be concluded that the impact of market activities on the performance of Jalan Martapura Lama KM 05 indicated by the degree of saturation (DS) and the value of road level of service with the optimum DS is 0,68 with the value of level of road service is C on Thursday’s afternoon rush hour and the minimum DS is 1.34 with the value of level of road service is F on Wednesday’s morning rush hour. With a total frequency of occurrences and side friction class of 571 frequencies, the maksimum friction is incoming and outgoing vehicles on area alongside roads (EEVs) of 446 occurrences on Tuesday in the morning rush hour.

Kathmandu Valley, Nepal, has severe air pollution, although few studies examine air pollution and health in this region. To the best of our knowledge, no previous studies in Nepal used time-activity diaries or conducted personal monitoring of individuals' exposures. We investigated personal exposure of particulate matter (PM) with aerodynamic diameter ≤2.5 μm (PM(2.5)) by location, occupation, and proximity to roadways. PM(2.5) monitoring, time-activity diary, respiratory health questionnaire, and spirometer testing were performed from 28 June 2009 to 7 August 2009 for 36 subjects, including traffic police (TP), indoor officer workers next to main road (IOWs_NMR) and away from main road (IOWs_AMR), in urban area (UA), urban residential area, and semi-UA (SUA). TP had the highest exposure of all the occupations (average 51.2 μg/m(3), hourly maximum >500 μg/m(3)). TP levels were higher at the UA than other locations. IOW_NMR levels (averaged 46.9 μg/m(3)) were higher than those of IOW_AMR (26.2 μg/m(3)). Exposure was generally higher during morning rush hours (0800-1100 hours) than evening rush hours (1500-1800 hours) for all occupations and areas (78% of days for TP and 84% for urban IOW). PM(2.5) personal exposures for each occupation at each location exceeded the World Health Organization ambient PM(2.5) guideline (25 μg/m(3)). Findings suggest potential substantial health impacts of air pollution on this region, especially for TP.

The study analyzed aspects of reducing the environmental impact of transport based on reducing the time to find parking for a car. The time spent by drivers searching for parking in the central part of the metropolis was analyzed. Data on the amount of time spent was obtained by interviewing drivers. The survey was conducted after completing a task to find parking in the central part of the metropolis at a certain time of the day (morning rush hour, daytime, evening rush hour). The data obtained reflect the time spent by drivers searching for parking in the central part of megacities; the data allows us to estimate the amount of environmental load arising from the “useless” movement of vehicles in the center of the metropolis, arising from the lack of free parking spaces. These studies can be used in the development of parking space planning programs and environmental programs aimed at improving the environmental situation in cities.

Particulate matter and carbon monoxide multiple regression models using environmental characteristics in a high diesel-use area of Baguio City, Philippines

Verification of a source-oriented externally mixed air quality model during a severe photochemical smog episode

Network Congestion, Braess Paradox and Urban Expressway System

Abstract. The Mexico City Metropolitan Area (MCMA) study in April 2003 had measurements of many atmospheric constituents, including OH and HO2. It provided the first opportunity to examine atmospheric oxidation in a megacity in a developing country that has more pollution than typical U.S. and European cities. At midday, OH typically reached 0.35 pptv (~7×106 cm−3), comparable to amounts observed in U.S. cities, but HO2 reached 40 pptv, more than observed in most U.S. cities. The OH reactivity was also measured, even during the highly polluted morning rush hour. MCMA's OH reactivity was 25 s−1 during most of the day and 120 s−1 at morning rush hour, which was several times greater than has been measured in any U.S. city. Median measured and modeled OH and HO2 agreed to within combined uncertainties, although for OH, the model exceeded the measurement by more than 30% during midday. OH production and loss, which were calculated from measurements, were in balance to within uncertainties, although production exceeded loss during morning rush hour. This imbalance has been observed in other cities. The HO2/OH ratio from measurements and steady-state analyses have essentially the same dependence on NO, except when NO was near 100 ppbv. This agreement is unlike other urban studies, in which HO2/OH ratio decreased much less than expected as NO increased. As a result of the active photochemistry in MCMA 2003, the median calculated ozone production from measured HO2 reached 50 ppb h−1, a much higher rate than observed in U.S. cities.

Some urban road tunnels serve as the main traffic access routes for residents in the surrounding large communities. The traffic congestion is a common phenomenon during rush hours inside this kind of tunnel. In order to learn about the environmental parameters inside tunnel during the evening rush hour, a comprehensive measurement in a typical commuting tunnel is conducted. The thermal environment parameters and air pollutant distribution along the tunnel are measured simultaneously. The results show that the traffic volume, vehicle speed and air velocity inside tunnel take on the obvious temporal and spatial discrepancy. There are the average 4.58°C air temperature rise and 96μg/m3 PM2.5 concentration rise from the tunnel entrance to the tunnel exit. The PM2.5 concentration at the tunnel exit is about 2.67 times of the 24-hour average limit of Chinese standard. The rise gradients of the air temperature and PM 2.5 concentration during the evening rush hour is given out.

Diurnal variation of PM2.5 mass concentration is analyzed based on data of BAOLIAN (representing urban area) and SAHNDIANZI BAP-Station (representing rural area) from 2005 to 2014. Furthermore, the influence of meteorological factors was also discussed. The results showed that 10-year-average diurnal variation of PM2.5 mass concentration in urban area had a two-peak pattern being coincident with rush-hour. However, it became clear only after 2007. The monthly (including seasonal) variation presented the change from one-peak pattern to two-peak pattern with the max mass concentration appearing in the morning or late afternoon during rush hour. The mass concentration in the morning rush hour reached its maximum between May and August which was to some degree related with weak wind and high relative humidity as well as great water vapor pressure (indicating the absolute water content in the air). But the smaller variety of mass concentration in the late afternoon attributed to the thicker mixing layer, higher wind speed and more showers. By contraries, it went up greatly after 4 pm in Nov., Dec., Jan. and Feb.. One of the reasons was that the height of mixing layer top decreased sharply. Besides, in some severely and seriously polluted days, the PM2.5 mass concentration increased after morning rush hour till afternoon which was different from the mean pattern and that in moderately polluted day. The main mechanism attributed to the aerosol from aerial source around brought by south wind to Beijing. The more severe the pollution was, the greater the daily concentration fluctuated. The range of PM2.5 diurnal variation was determined by the max wind speed and daily change of relative humidity in a day. Besides, it also extended the diurnal variation of concentration when the south wind speed reached 4-6 m·s-1 in the afternoon. In rural area, the mean diurnal variation of PM2.5 mass concentration showed a one-peak pattern. And the time of concentration reaching its maximum was ahead of that of urban area. Moreover, the values in the day time during May and July were higher than that in winter. These results would be helpful to make policy for finer emission control when the atmosphere is in lower diffusivity situation.

Most public health physical activity guidelines now encourage people to look for opportunities to accumulate physical activity throughout the day. Climbing stairs in lieu of riding escalators is a prime opportunity to make healthier choices that promote active living. The purpose of this investigation was to examine the effects of pedestrian commuter traffic on choices to ride an escalator, walk up an escalator, or walk up adjacent stairs in a busy urban subway station at rush hour. A total of 9766 commuters were observed by two recorders for a 2.5-hour period during the morning rush hour over 8 weeks as to whether the commuters walked up stairs or rode an adjacent escalator in a subway station. The number of observations per 5-minute block was recorded, and an index of commuter traffic was computed. Demographic information and use of escalators/stairs were also recorded. An urban subway station with a two-flight staircase adjacent to an escalator. Adult commuters travelling to work during the morning rush hour. Physical activity choices were examined in relation to commuter traffic. Demographic information, such as age, race, and weight status, were also considered. A χ(2) analysis was used to examine differences in proportions across variables of interest. Means were compared by using multivariate analysis of variance, and confidence intervals were computed. During the least-heavy commuter traffic period, only 11.2% of commuters chose to walk up the stairs, whereas significantly more did so during moderate 18.7% and high 20.8% commuter traffic periods (χ(2) = 61.8, p < .001). During low-traffic times, significantly more commuters (21.4%) walked up the escalators compared with moderate-traffic (18.0%) or high-traffic (18.3%) periods. African-American commuters passively rode the escalator more (68.2%) than white commuters (56.7%), and their patterns were less affected by commuter traffic (p < .05). Congestion in public places can have a significant effect on opportunities for choosing active versus passive options in moving through public places. Urban planners should consider this when designing facilities in busy locations.

In this study, we have assessed the three-dimensional (3-D) spatial extent of near-road air pollution around a signalized intersection in a densely populated area using collaborating methodologies of stationary measurements, drone monitoring, and atmospheric dispersion modeling. Stationary measurement data collected in the roadside apartment building showed a substantial effect of emitted pollutants, such as nitrogen oxides (NOx), black carbon (BC), and ultrafine particles (UFPs), especially during the morning rush hours. Vertical drone monitoring near the road intersection exhibited a steeper decreasing trend with increasing altitude for BC concentration rather than for fine particulate matter (PM2.5) concentration below the apartment building height. Atmospheric NOx dispersion was simulated using the weather research and forecasting (WRF) and computational fluid dynamics (CFD) models for the drone measurement periods. Based on the agreement between the measured BC and simulated NOx concentrations, we concluded that the air pollution around the road intersection has adverse effects on the health of residents living within the 3-D spatial extent within at least 120 m horizontally and a half of building height vertically during the morning rush hours. The comparability between drone monitoring and WRF-CFD modeling can further guarantee the identification of air pollution hotspots using the methods.

Spatial-temporal heterogeneity of air pollution: The relationship between built environment and on-road PM2.5 at micro scale

Site environments and instrumental characteristics of carbon dioxide (CO2) measurements operated by local governments in the Kanto Plain, the center of which is Tokyo, were summarized for this study. The observation sites were classified into environments of three types: urban, suburban, and woodland. Based on a few decades of accumulated hourly data, the diurnal and seasonal variations of CO2 concentrations were analyzed as a composite of anomalies from annual means recorded for each site. In urban areas, the highest concentrations appear before midnight in winter. The second peak corresponds to the morning rush hour and the strengthening of the inversion layer. Suburban areas can be characterized as having the highest concentration before dawn and the lowest concentration during the daytime in summer in association with the activation of respiration and photosynthesis of vegetation. In these areas, concentration peaks also appear during the morning rush hour. Woodland areas show background features, with the highest concentration in early spring, which are higher than the global background by about 5 ppmv.