The overall ecological environmental quality of Hainan province including ambient air, surface water and coastal waters maintains good in 2011, according to an official report about the environmental states released by the Department of Land Environment & Resources of Hainan Province on June 4, 2012.
The province's urban sewage centralized treatment reached 72% in 2011, and 89.7% of the monitored river water quality reached or was better than Class Level of the national surface water standards.
The number of days with excellent air quality in Hainan reached 100% last year, with 96.7 percent of the monitored days was in Grade I. The daily average concentration of sulfur dioxide, nitrogen dioxide was in line with national 1st class standard, and respirable particulates matters had slight impact on regional air quality.
The report also showed that the air quality of Bawang Hill National Forest Park, Jianfeng Tropical Rainfroest, Wuzhi Mountain and other six main forest tourism area of Hainan were excellent, with the average air anion concentration over 2100/cc, surpassing the standard of 1000-1500/cc required by the World Health Organization. The annual average equivalent sound level of the monitored urban road traffic noise, ranging from 63.4 to 69.9 dB, met the standard of national requirement.
The ecological environmental states of all cities and counties across the province were excellent with 60.5% forest coverage and rich biodiversity.