Figure 2.

Sand dust particle and aerosolized air pollutant levels (A) Daily median levels of sand dust particles (open circles) and aerosolized air pollutants (closed squares). A heavy dust day was defined as an hourly sand dust particle level >0.1 km⁻¹ using light detection and ranging data. Arrows indicate heavy dust days; (B) The time above 0.1 km⁻¹ was based on hourly levels. Eight heavy dust days, 7–10 March, 17 March, 20 March, 6 April, and 30 April, occurred during the study period.