In [1]:
PM=int(input('请输入今日的PM2.5指数'))
if 0<=PM<35:
print('空气质量优')
elif 35<=PM<75:
print('空气质量良')
elif 75<=PM<115:
print('轻度污染，请减少外出并佩戴口罩')
elif 115<=PM<150:
print('中度污染，应减少户外活动，外出时佩戴口罩，敏感人群应尽量避免外出。')
elif 150<=PM<250:
print('重度污染，避免外出，开启空气净化器')
else:
print('我也很绝望了')