The influence of odd–even car trial on fine and coarse particles in Delhi. (June 2017)

• Record Type: Journal Article
• Authors: Kumar, Prashant; Gulia, Sunil; Harrison, Roy M.; Khare, Mukesh
• Is Part Of: Environmental pollution. Volume 225(2017)
• Page Start: 20
• Page End: 30
• Publication Date: 2017-06
• Subjects: Living labs -- Odd–even car trial -- PM10 and PM2.5 -- Pollution exposure -- Traffic emissions; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2017.03.017
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The odd-even car trial scheme, which reduced car traffic between 08.00 and 20.00 h daily, was applied from 1 to 15 January 2016 (winter scheme, WS) and 15–30 April 2016 (summer scheme, SS). The daily average PM2.5 and PM10 exceeded national standards, with highest concentrations (313 μg m −3 and 639 μg m −3, respectively) during winter and lowest (53 μg m −3 and 130 μg m −3 ) during the monsoon (June–August). PM concentrations during the trials can be interpreted either as reduced or increased, depending on the periods used for comparison purposes. For example, hourly average net PM2.5 and PM10 (after subtracting the baseline concentrations) reduced by up to 74% during the majority (after 1100 h) of trial hours compared with the corresponding hours during the previous year . Conversely, daily average PM2.5 and PM10 were higher by up to 3–times during the trial periods when compared with the pre–trial days . A careful analysis of the data shows that the trials generated cleaner air for certain hours of the day but the persistence of overnight emissions from heavy goods vehicles into the morning odd–even hours (0800–1100 h) made them probably ineffective at this time. Any further trial will need to be planned very carefully if an effect due to traffic alone is to be differentiated from the larger effect caused by changes in meteorology and especially wind direction. Graphical abstract: Highlights: Effect of odd–even traffic trial on PM2.5 and PM10 concentrations in Delhi are analysed. PM2.5 and PM10 were the highest during winter and lowest during monsoon season. High tempo–spatial variability in baseline PM was observed at different sites. Unlike PM10, the effect of odd–even was highest on PM2.5 during peak traffic hours. Persistence of overnight emissions from heavy goods vehicles made early odd–even hours ineffective. Abstract : The odd–even car trial in Delhi reduced PM levels in certain hours but the persistence of overnight emissions from trucks made them ineffective during the morning odd–even hours.