Markov Chain-Based Acute Effect Estimation of Air Pollution on Elder Asthma Hospitalization

Table 4

Concentration threshold of Chinese Ministry of Environmental Protection for each pollutant.

Pollutant	Concentration threshold
	Primary standard	Second standard
PM2.5	35 μg/m^3	75 μg/m^3
PM10	50 μg/m^3	150 μg/m^3
SO2	50 μg/m^3	150 μg/m^3
NO2	80 μg/m^3	—

Abbreviations are the same as in Table 1. — indicates no existence.