Monitoring and Modelling the Trends of Primary and Secondary Air Pollution Precursors: The Case of the State of Kuwait

Table 1

Standard USEPA methodology for annual population risk (APR) and hazard index (HI) calculations used by Al-Salem and Bouhamrah [27]; Al-Salem and Al-Fadhlee [28].

Equation/correlation	Notes
OX = 𝐶O3 + 𝐶NO𝑥 − 𝐶NO	Used for data filtration, where OX is the concentration of oxides in the ambient (ppb), 𝐶O3, 𝐶NO𝑥 and 𝐶NO are the concentrations in ppb of ozone, NOx and nitric oxide, respectively.
𝐸=𝐶⋅CR⋅EF⋅EDBW⋅AT	Where 𝐶 is the contaminant concentration (mg⋅m^-3); CR is the contact rate in m^3day^-1; EF is the exposure frequency in days per year; ED exposure duration (year); BW is the average human body weight (kg); AT is the averaging time in hours/year.
APR = Risk factor × Population/lifetime	APR is the annual population risk
HI = Σ (𝐶𝑖/PEL𝑖)	Where 𝐶𝑖 is the concentration of 𝑖 in mg/m^3; PEL𝑖 is the permissible exposure limit for 𝑖 in mg/m^3.