Particulate Matter is a mixture of solid particles and liquid droplets. It can be classified into 2 groups, PM2.5 and PM10. The difference between them is the measurement of particle size. PM2.5 refers to particles with size of less than 2.5 μm while PM10 refers to particles with size of less than 10 μm. Hence, with a smaller size, PM2.5 particles implicates heart diseases while PM10 particles affects the lungs.