Objective  to understand the cognitive situation of Pinghu residents, related to PM_2.5, which will provide basis for the government to formulate relevant policy.

Methods  with unified questionnaires used to investigate residents aged between 17 and 65, and living in Pinghu more than three months. The survey contents included the residents' cognition to the knowledge related to PM2.5 and whether to take self-protection measures in the air pollution. Single factor chi-square test was adopted for rate comparison.

Results  398 valid questionnaires (male 195, female 203, median age 32 years, range 17 to 65 years) were effectively responded, from 420 interviewees, with a response rate of 94.76%.The awareness rate of PM_2.5 was 75.13%(299/398),the awareness rate of 17 to 25 years old group up to 85. 96%. The knowledge awareness with bachelor degree and above(96%)is significantly higher than high school and below (53.1%), the difference was statistically significant (P<0.01);Civil servants or state-owned business unit on-the-job personnel awareness (90.32%) is much higher than the farmers (34.55%),the difference was statistically significant (P<0.01).Respondents would be to take protective measures in air pollution and will adopt wear masks most (78.39%,312/398).

Conclusion  The cognitive level of people to PM_2.5 remained to be improved, especially for farmers and older people.