If there are even dates on 3 Sundays in a month, then the 5th of this month is______ ．

In a month, there are three Sundays with even dates. The 2nd of this month is Sunday, the 2nd, the 9th, the 16th, the 23rd and the 30th of this month are Sundays, and five Sundays. Then the 5th of this month is Wednesday

There are even dates of three Sundays in a month. Please calculate the day of the 15th of this month

There are only two even dates in the four consecutive Sundays of each month, so there must be five Sundays in this month. The first Sunday is the 2nd, the third Sunday is the 16th (16 = 2 + 14), and the fifth Sunday is the 30th (30 = 2 + 28), because the 1st is Saturday, the 1st + 14 is 15, and the 15th is also Saturday. Therefore, the 15th of this month is Saturday

There are even dates of three Sundays in a month. Please calculate the day of the 15th of this month

Problems of API and AQI
I don't study in the environment, but recently a job involved this problem. I didn't understand the information I found on the Internet very well,
1. What are the concepts of API and AQI, and what are the differences between them
2. What are the calculation formulas of API and AQI, and what are the judgment criteria of their grades?

Air pollution index (API) is a method to reflect and evaluate air quality. It is to simplify the concentration of several air pollutants in routine monitoring into a single conceptual numerical form, and characterize the air quality status and air pollution level by classification. The results are simple, intuitive and easy to use

What is the source of air pollution? What is the relationship between air pollution index and air quality?

The main sources of air pollution are automobile exhaust pollution, industrial and civil boiler, coal stove, incinerator pollution, construction dust, air pollution caused by spontaneous combustion of nature, chemical process, volcanic eruption, etc

How does air pollution index define air quality?

The air pollution index is divided into 7 grades: 0 ~ 50, 51 ~ 100, 101 ~ 150, 151 ~ 200, 201 ~ 250, 251 ~ 300 and more than 300, corresponding to 7 grades of air quality. The higher the index is, the higher the grade is, indicating that the more serious the pollution is, and the more obvious the impact on human health is. The air pollution index is 0 ~ 50, and the air quality is grade I, so the air quality is excellent, The air pollution index is 51 ~ 100, the air quality is grade II, the air quality is good. At this time, the air quality is considered acceptable, except for a few people who are particularly sensitive to certain pollutants, it is not harmful to public health. The air pollution index is 101 ~ 150, the air quality is grade III (1), At this time, the health status of people who are more sensitive to pollutants, such as children and the elderly, patients with respiratory diseases or heart diseases, and people who like outdoor activities, will be affected, but there is basically no impact on healthy people. The air pollution index is 151 ~ 200, the air quality level is III (2), and the air quality status belongs to light pollution, Almost everyone's health will be affected, especially for sensitive people. The air pollution index is 201 ~ 300, and the air quality level is IV (1) and IV (2). The air quality belongs to moderate and moderate heavy pollution. At this time, everyone's health will be seriously affected. The air pollution index is greater than 300, and the air quality level is v, The air pollution index can remind the public, especially those who are sensitive to air pollution, such as patients with heart disease or respiratory disease, to take preventive measures when necessary

What are the effects of air quality on human health

Quality
The common method is to raise some oxygen releasing plants indoors to change the air. Such as cactus and other more green plants. But also note that these plants will absorb oxygen at night, do not plant too much in the bedroom!

If there are even dates on 3 Sundays in a month, then the 5th of this month is______ ．