Strategies for reduction of episodic risk of PM 10 by controlling industrial and traffic emissions of SO 2 and NO 2 and meteorological parameters

Abstract

The purpose of this study was to provide effective strategies for ambient air quality management to ameliorate ambient PM₁₀ concentrations. The study investigated the association of meteorological parameters with occurrence of PM₁₀ episodes due to emissions from local sources. Spearman's rank correlations of atmospheric NO₂ and SO₂ and meteorological parameters with daily PM₁₀ concentrations, monitored in urban centres in Changsha, were conducted. The conditional logistic regression and time-stratified case-crossover were used to analyse effects of different local sources with adjustment for different meteorological parameters. Their association with diurnal hourly ambient PM₁₀ concentration and occurrence of PM₁₀ episodes was determined. The results showed that the frequency and risks of occurrence of PM₁₀ episodes were highest in winter and lowest in summer. An increase in atmospheric NO₂ concentration was illustrated to be more likely to induce PM₁₀ episode than SO₂. Temperature and rainfall are key meteorological parameters to be adjusted for pollution mitigation to effectively reduce occurrence risk of PM₁₀ episodes. The episodic risk could be mitigated by controlling emission sources of SO₂ and NO₂. Significant reduction in PM₁₀ concentrations can be achieved when simultaneously adjusted for temperature or rainfall. The episodic risk could be further minimized by controlling the meteorological conditions (e.g. surface temperature, atmospheric pressure and urban ventilation) during early morning period (03:00–06:00) and by controlling fuel use and traffic during late afternoon period (17:00–18:00). Implementation of air quality management strategies proposed should be crucial to mitigate pollution risk of particulate matter episodes and to protect human health and the environment.