How many different standards have a PM of 0.02 g/kWh?
CREATE TABLE table_2780146_6 (
    standard VARCHAR,
    pm__g_kwh_ VARCHAR
)
SELECT COUNT(standard) FROM table_2780146_6 WHERE pm__g_kwh_ = "0.02"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: How many different standards have a PM of 0.02 g/kWh? ### Input: CREATE TABLE table_2780146_6 (
    standard VARCHAR,
    pm__g_kwh_ VARCHAR
) ### Response: SELECT COUNT(standard) FROM table_2780146_6 WHERE pm__g_kwh_ = "0.02"